Hitherto, photo studio and the like perform a photographic work using a background curtain. However, for such a photographic work, there is used a large background curtain to provide a sufficient background, and there is a need to prepare a wide photographic working space. Further, exchanges of the background curtain take a great deal of time, and as a result, it involves a high cost of photographic work.
Thus, in order that a person can enjoy photography with ease, it is desired to develop a small type of photographic system without need of a large background curtain and a wide photographic working space, as needed for the conventional photographic work. According to such a small type of photographic system, there is performed a photographic work before some provisional background instead of the background curtain as mentioned above. Therefore, there is considered an application of background replacing processing, in which a background of a photographic image is replaced with a background desired by a custom, to the photographic image obtained through photography.
As an example of technology as to the background replacing processing, for example, there is known processing referred to as chromakey processing in which photography is carried out through an arrangement of background panel coated with blue and the like back the subject, and in a photographic image obtained through the photography, a portion of the same color as the background panel and a portion of the different color from the background panel are distinguished from one another in form of a background area of the photographic image and a subject area, respectively, so that the portion, which is discriminated as the background area of the photographic image, is replaced with a desired background.
According to the chromakey processing, in the event that a shadow of the subject of the photographic image is formed on the background panel, it would happen that the shadow disturbs a distinction between the subject area and the background area. In view of the foregoing, in the event that a photograph of an image of interest of the chromakey processing is taken, there is proposed technology that as the background, a background panel of a panel light emission is used, so that a photography is carried out in a state that the shadow of the subject on the background panel is negated by light emitted from the background panel (for example, cf. Japanese Patent Application Laid Open Gazette Tokukai 2000-224410 (pages 3-10, FIG. 3)). Japanese Patent Application Laid Open Gazette Tokukai 2000-224410 further discloses chromakey processing wherein when a portion, which is discriminated as a subject area, is synthesized with a desired background, a color tone of the portion discriminated as the subject area is controlled to a color tone according to the color tone of the desired background, so that there is created a composite image in which the subject looks as it naturally matches for the desired background.
Further, there is proposed technology that two photographic images are obtained through performing photography under two lighting conditions of a state in which a lighting directed to the subject turns on at a place where the back of the subject opens, for example, out of doors, and a state in which the lighting turns off, and in those two photographic images, a portion that is different in luminance and a portion that is same in luminance are distinguished as a subject area and a background area of the photographic images, respectively, so that the portion discriminated as the background area of the photographic images is replaced with a desired background (for example, cf. Japanese Patent Application Laid Open Gazette Tokukai Hei 10-210340 (pages 2-3, FIG. 1)).
By the way, for example, in the event that photography is carried out taking a person as the subject, it often happens that the photography is carried out in a state that a background appears through hairs and scarves of the woman as the subject. Thus, it often happens that the background appears through a part of the subject on the photographic image. In the event that as to the photographic image as mentioned above, the background is replaced in accordance with technologies disclosed in Japanese Patent Application Laid Open Gazette Tokukai 2000-224410 (pages 3-10, FIG. 3) and Japanese Patent Application Laid Open Gazette Tokukai Hei 10-210340 (pages 2-3, FIG. 1), and general chromakey processing, it often happens that there is created unnatural background-replaced images such as an image in which a part of the edge of the subject together with the background is replaced by another background, and an image in which the old background before replacement appears through a part of the subject.